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Vertex distance is the distance between the back surface of a corrective lens, i.e. glasses (spectacles) or contact lenses, and the front of the cornea. Increasing or decreasing the vertex distance changes the optical properties of the system, by moving the focal point forward or backward, effectively changing the power of the lens relative to ...
The vertex set (of an undirected graph) and the distance function form a metric space, if and only if the graph is connected. The eccentricity ϵ(v) of a vertex v is the greatest distance between v and any other vertex; in symbols, = (,).
In glasses with powers beyond ±4.00D, the vertex distance can affect the effective power of the glasses. [4] A shorter vertex distance can expand the field of view, but if the vertex distance is too small, the eyelashes will come into contact with the back of the lens, smudging the lens and causing annoyance for the wearer.
BVD Back vertex distance is the distance between the back of the spectacle lens and the front of the cornea (the front surface of the eye). This is significant in higher prescriptions (usually beyond ±4.00D) as slight changes in the vertex distance for in this range can cause a power to be delivered to the eye other than what was prescribed.
Angle AOB is a central angle. A central angle is an angle whose apex (vertex) is the center O of a circle and whose legs (sides) are radii intersecting the circle in two distinct points A and B. Central angles are subtended by an arc between those two points, and the arc length is the central angle of a circle of radius one (measured in radians). [1]
The numbers beside the vertices indicate the distance from the root vertex. In mathematics and computer science, a shortest-path tree rooted at a vertex v of a connected, undirected graph G is a spanning tree T of G, such that the path distance from root v to any other vertex u in T is the shortest path distance from v to u in G.
A ball (also known as a neighborhood ball or distance ball) is the set of all vertices that are at most distance r from a vertex. More formally, for a given vertex v and radius r, the ball B(v,r) consists of all vertices whose shortest path distance to v is less than or equal to r. bandwidth
A vertex of an angle is the endpoint where two lines or rays come together. In geometry, a vertex (pl.: vertices or vertexes) is a point where two or more curves, lines, or edges meet or intersect. As a consequence of this definition, the point where two lines meet to form an angle and the corners of polygons and polyhedra are vertices. [1] [2] [3]